I can imagine unmanned freighters in 20-30 years,
I cant. As a freight pilot in 20 years I will be flying aircraft that are being delivered today. We mainly buy 20+ year old aircraft.
The other point is GPS is going on 20 years old and we still cant use it for approaches, So why would UAV's have any shorter a gestation to commercial certification. Thirdly can UAV's fly non radar enviroment NDB to circling approaches to greek islands on changeover day. Er No.
Bit more work required methinks.